Description: The Aging and Alzheimer's Research Center Laboratory Animal Core operates as a shared resource which facilitates, enriches and coordinates animal model studies for four of the five component projects in this proposal. This Core has, over previous grant and project periods, developed and maintained barrier-sustained, disease-free colonies of conventional, aged, ancient, lifetime (>39 months) caloric restricted, and neurologically modeled rats in order to reduce data-compromising animal variables for new and ongoing studies. We have eliminated infectious agents from all experimental colonies, constructed and renovated new barrier housing areas, established improved environmental conditions for housing behavioral modeled research animals, with behavioral testing laboratories contiguous to animal housing rooms. One specific aim of this Core component is to continue to provide specialized maintenance of barrier sustained transgenic, knockout and control mice, transplant, antioxidant fed, caloric-restricted, modeled and control aged F-344 NIA rats, as well as young and aged Sprague-Dawley rats. A second specific aim is to provide regular, comprehensive health evaluations on all project animals, and diagnostic, gross and histopathological examinations on all experimental animals at experiment termination or when euthanasia is required due to disease development. The Core will also conduct serological surveillance of all experimental animal colonies to document continuing virus and mycoplasma-free status and provide continuous consultation on laboratory animal genetics, model development and training in aged animal biology. A third specific aim is to produce congenic, inbred, hyperoxia-resistant rats on a Fisher-344 genetic background from hyperoxia resistant rats presently on an outbred Sprague-Dawley background. In a fourth specific aim, Core personnel will maintain the Core-developed, automated database that includes monitoring and tracking of all project animals. Animals are uniquely identified with electronic, transponding microchips and the Core will input all animal health and final pathological evaluations at necropsy into the database which is networked to and accessible by all project investigators.